1. Field of the Invention
The present invention relates to a power conversion apparatus for converting AC power supplied from an AC power source to DC power.
2. Description of Related Art
Japanese Patent Application Laid-open No. 2006-129619 describes a power conversion apparatus capable of preventing malfunctioning when the output current thereof is detected to have decreased under an environment where the output voltage of an AC power source varies greatly. This power conversion apparatus is configured to set a command value of the output current thereof below a predetermined value if the input voltage supplied from the AC power source is detected to be smaller than a predetermined value, to prevent the output current from being determined to have decreased below the command value to thereby prevent malfunctioning.
However, since the power conversion apparatus is configured to determine the command value of the output current based on the input voltage, a time necessary to make a determination whether the input voltage is smaller than the predetermined value may cause a problem. That is, since the input voltage is an AC voltage, and accordingly a peak value of the AC voltage has to be detected to determine the value of the input voltage, it may take a half-period of the AV voltage to make the determination at longest.
Furthermore, when the power conversion apparatus described in the above patent document is used for a system including an AC-DC converter and a DC-DC converter which are mounted on different units, communication devices for enabling communication between the AC-DC converter and the DC-DC converter are required. In this case, there may occur other problems such as degradation of responsiveness due to communication delay, increase in parts count due to mounting of communication equipment, or reliability degradation due to interposition of the communication devices.